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5 * This code is derived from software contributed to Berkeley
6 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
7 * Support code is derived from software contributed to Berkeley
8 * by Atsushi Murai (amurai@spec.co.jp).
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34 * @(#)cd9660_bmap.c 8.3 (Berkeley) 1/23/94
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/vnode.h>
43 #include <sys/mount.h>
45 #include <isofs/cd9660/iso.h>
46 #include <isofs/cd9660/cd9660_node.h>
49 * Bmap converts a the logical block number of a file to its physical block
50 * number on the disk. The conversion is done by using the logical block
51 * number to index into the data block (extent) for the file.
55 struct vop_bmap_args /* {
58 struct bufobj **a_bop;
64 struct iso_node *ip = VTOI(ap->a_vp);
65 daddr_t lblkno = ap->a_bn;
69 * Check for underlying vnode requests and ensure that logical
70 * to physical mapping is requested.
72 if (ap->a_bop != NULL)
73 *ap->a_bop = &ip->i_mnt->im_devvp->v_bufobj;
74 if (ap->a_bnp == NULL)
78 * Compute the requested block number
80 bshift = ip->i_mnt->im_bshift;
81 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT);
84 * Determine maximum number of readahead blocks following the
90 nblk = (ip->i_size >> bshift) - (lblkno + 1);
93 else if (nblk >= (MAXBSIZE >> bshift))
94 *ap->a_runp = (MAXBSIZE >> bshift) - 1;